Try-square.



J. 'W. FRY & C. W. FISHER. TRY SQUARE.

APPLIOATIQN FILED MAR. 31, 1908.

900,995, Patented 000.13,1908.

ATTORNEY v WITNESSES UNITED sTA ns PATENT OFFICE.

JOHN WALTER FRY AND GARMAN WALTER FISHER, OF PHILADELPHIA, PENNSYLVANIA.

TRY-SQUARE.

Specification of Letters. Patent.

Patented Oct. 13, 1908.

To all whom it may concern:

Be it known that we, JOHN WALTER FRY and OARMAN WALTER FIsHER, citizens of the United States, residing in the city of Philadelphia, countyof Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Try-Squares, of

which the following is a full, clear, and complete disclosure, reference being had to the accompanying drawing, forming part of this specification.

This invention relates particularly to that class of try squares, in which the square is formed of two arms, which maybe taken apart for convenience in packing or transportation; and the main object of our invention is to provide an improved joint whereby the two arms of the square may be held rigidly together, but which permit of the arms bein quickly and easily separated, or as quic rly and easily joined together, as occas10n may require.

A further object of the invention is to provide a joint, which will not be liable to be injured during use, and which will be strong and rigid. V

In the accompanying drawing, Figure 1 is a perspective view of a square constructed in accordance with our invention, looking downward upon the face thereof; Fig. 2 a bottom plan View of the joint of the same Figs. 3 and 4 are detail perspectives of the members composing the square; and Fig. 5 is a section 011 ine 55 of Fig. 2.

Referring to the drawings, the square comprises two arms land 2 whicharejoined and ocked together as hereinafter described to form a right angle. One arm 1 is provided with a transverse dove-tailed or under-cut recess 3, which is about one-half as deep as the thickness of the arm, and the bottom face of the recess extends thefull width of the arm. The inneredge of this arm is cut away at the inner endthereof to form a substantially rectangular recess 4, one edge 5, of which is formed by a plane extending longitudinally of the arm perpendicular to the face thereof, and the other edge 6, of which extends transversely of the arm, and is preferably formed by an oblique plane substantially in alinement with the outer transverse edge of the recess 4. The inner edge of the arm is also provided with a substantially. rectangular recess 7, the inner side 8 of which extends longitudinally of the arm in alinement with the edge 5 of the outer recess 4,

F and the two recesses define the side edges of the dove-tailed tenon 9, the upper transverse edges of which are substantially in alinement with the transverse edges of the bottom of the transverse recess 3. The second arm 2 of the try square is provided on its upper side with a dove-tailed tenon 10 adapte to fit in the transverse dove-tailed recess 3, of the other arm, and the end of this tenon is provided witha longitudinal slot 11 to recelve the shank of the screw 12, which is threaded into the arm 1, the inner end of the slotted portion of the tenon being countersunk as at 13 to receive the head of the screw. The sides of the slot are preferably slightly beveled to make the opening in the top of the slot slightly wider than that at the bottom, so that it is not necessary to fully Withdraw the head of the screw from the slot before the two arms of the square may be drawn apart.

The under side of the second arm is provided with a dove-tailed recess 14 to receive the dove-tailed tenon 9 of the other arm, the inner corners '15 of the recess 14 being preferably rounded for convenience in construction, and the outer corners 16 of the corresponding tenon 7 are also accordingly rounded. The end edges 17 and 18 upon each side of the tenon 10 of the second arm are perpendicular to the face of the arm. 'I

The arms and their recesses are so proportioned that when the two arms are'placed together the recessed portions of each arm are filled by corresponding portions of the other arm to bring the joint tight, and all outside surfaces of the arms flush.

It is evident that as the screw 12 is tightened against the counter-sunk seat in the tenon 10, the slotted end of the tenon will be spread apart slightly to press the side edges of the tenon tightly against the dovetailed edges of its containing recess, and will contract again upon being released by the screw, thus forming a joint which will take up any slight looseness due to construction or wear. This efiiect might be increased by continuing the slot in the tenon inwardly beyond the screw as indicated by the dotted lines in the drawing. The simplicity and rigidity of this joint is apparent in the drawings where it may be noted that the full thickness of each of the arms comprising the square. butts against and is opposed by the full thickness of the other arm in two directions at right angles to each other, and ex' tending respectively longitudinally of each arm, so that practically the only stresses that may be brought to bear in the plane of the square upon the tenons of the joint are stresses extending longitudinally of the tenons which the tenons are well able to resist, which is obviously a much stronger construction than where the tenons are not thus protected and are subjected to transverse stresses extending in the plane of the square. It is also evident that by having two oppositely disposed dove-tailed tenons upon opposite sides of the joint and upon the opposite arms respectively, each tenon supports the other, and any tendency of the square to flex out of its normal fiat plane is largely overcome. The further condition of having each arm of the square abut for its full thickness against the other arm also contributes to maintain the arms in the same plane. It is also to be noted that there are no projections upon either arm of the square beyond the width or thickness of the arm, and therefore the square may be packed in a small space when taken apart and the tenons of the square being within the outer dimensions of the arms are protected from injury.

With this construction in mind, it is evident that the two arms of the square may be readily detached by merely loosening the screw 12, and withdrawing one arm from the other, and may be as readily put together and held rigidly in place by simply tightening the single screw.

Although this invention has been shown and described as applied to join two arms to form a right angled try square, it is obvious that the invention might be applied to join two arms to form any other angle, and that other changes might be made in the details of construction, within the scope of the appended claims without departing from the spirit of this invention or sacrificing any of the advantages thereof.

Having thus fully described our invention, what we claim and desire to secure by Letters Patent of the United States is:

1. A square comprising two arms, one of said arms being provided with a transverse dove-tailed recess in the face thereof, the lower surface of which extends the full width of the arm, and with recesses upon the inner edge of said arm upon opposite sides of said first mentioned recess forming a dove-tailed tenon upon the under side of said arm, a second member having a recessed portion to receive said dove-tailed tenon and having a dove-tailed tenon adapted to fit in the dove- 1taailed recess of the said first mentioned mem- 2. A square comprising two arms, one of said arms being provided with a transverse dove-tailed recess in the face thereof, the lower surface of which extends the full width of the arm, and with recesses upon the inner edge of said arm upon opposite sides of said first mentioned recess forming a dove-tailed tenon upon the under side of said arm, the outer end of said tenon being substantially in alinement with the under edge of said arm, a second member having a recessed portion to receive said dove-tailed tenon and having dove-tailed tenon adapted to fit in the dovetailed recess of the said first mentioned memher.

3. A square comprising two arms, one of said arms being provided. with a transverse dove-tailed recess in the face thereof, the lower surface of which extends the full width of the arm, and with recesses upon the inner edge of said arm upon opposite sides of said first mentioned recess forming a dove-tailed tenon upon the under side of said arm, a second member having a recessed portion to receive said dove-tailed tenon and having a dove-tailed tenon adapted to '[it in the dovetailed recess of the said first mentioned member, and means to hold said members together.

4. A square comprising two arms, one of said arms being provided with a transverse dove-tailed recess in the face thereof, the lower surface of which extends the full width of the arm, and with recesses upon the inner edge of said arm upon opposite sides of said first mentioned recess forming a dove-tailed tenon upon the under side of said arm, a second member having a recessed portion to re ceive said dovetailed tenon and having a dove-tailed tenon adapted to fit in the dovetailed recess of the said first mentioned member, said first mentioned tenon having a longitudinal slot at the end thereof, and tightening means extending through said slot.

5. A square comprising two arms, one of said arms being provided with a transverse dove-tailed recess in the face thereof, the lower surface of which extends the full width. of the arm, and with recesses upon the inner edge of said arm upon opposite sides of said first mentioned recess forn'iing a dove-tailed tenon upon the under side of said arm, a second member having a recessed. portion to receive said dove-tailed tenon and having a dove-tailed tenon adapted to 'lit in the dovetailed recess of the said first mentioned member, said first mentioned tenon having a longitudinal slot at the end thereof, and a tightening screw extending through said slot and threaded into said second member.

6. A square comprising two arms, one of said arms having spaced recesses upon one side edge, forming a dove-tailed tenon, and.

having a transverse dove-tailed recess upon one side, and the other of said arms having spaced notches upon one end edge forming a dove-tailed tenon, and a longitudinal dovetailed recess upon the opposite side, the

tenon of each arm fitting into. the recess of the other arm.

7 A square comprising two arms, one of said arms having a transverse tenon projecting adjacent one side thereof and a transverse recess in the other side thereof, and the other arm having a corresponding longitudinal recess and a longitudinal'tenomthe tenon of each arm fitting slidingly into the recess of the other arm and the outer end of said first mentioned tenon being substantially in alinement with the inner edge of its arm.

8. A square comprising two arms, one of said arms having a tenon projecting from one edge adjacent to one side thereof, and a recess in the other side thereof, and the other arm having a corresponding recess and tenon, the tenon of each arm fitting slidingly into the recess of the other arm, one of said arms having a rectangular recess u on one edge extending the full thickness of said arm to receive the end of the other arm.

9. A square comprising two arms, one of said arms having a tenon projecting from one edge adjacent to one side thereof and a recess in the other side thereof, and the other arm having a corresponding recess and tenon, the tenon of each arm fitting slidingly into the recess of the other arm, one of said tenons having a slot and means extending through said slot to hold said arms together, and one of said arms having a rectangular recess upon one edge extending the full thickness of said arm to receive the end of the other arm.

10. A square comprising two arms, one of said arms having a transverse tenon formed adjacent one side thereof and the other arm having a corresponding longitudinal recess to receive said tenon, the end edge of said tenon not projecting beyond the inner edge of its arm.

11. A try-square comprising two arms, the one of said arms having spaced recesses upon one side edge forming a tenon, and having an undercut recess upon one side of said arm, the other of said arms having spaced notches upon one end edge, forming a tenon, and an undercut recess u on the other side of said arm, the tenon 0 each arm fitting into the recess of the other arm.

12. A try-square comprising two arms, the one of said arms having spaced recesses upon one side edge forming a tenon, and having an undercut recess adjacent said tenon, the other of said arms having spaced notches upon one end edge, forming a tenon, and an undercut recess adjacent said second tenon, the tenon of each arm fitting into the recess of the other arm.

13. A try-square comprising two arms, one

of said arms having spaced recesses upon one side edge forming a tenon which does not project beyond the edge of said arm, and having a recess upon one side, and the other of said arms having spaced notches upon one end edge forming a tenon, and a longitudinal recess upon one side, the tenon of each arm fitting into the recess of the other arm.

14. A separable try-square comprising two arms, one of said arms having a recess upon one side edge thereof forming a tenon- 

